xz: Refactor duplicated check for custom suffix when using --format=raw

src/xz/args.c

@@ -724,6 +724,14 @@ args_parse(args_info *args, int argc, char **argv)
 			&& opt_mode != MODE_LIST))
 		coder_set_compression_settings();
 
+	// If raw format is used and a custom suffix is not provided,
+	// then only stdout mode can be used when compressing or decompressing.
+	if (opt_format == FORMAT_RAW && suffix_is_set() && !opt_stdout &&
+			(opt_mode == MODE_COMPRESS ||
+			opt_mode == MODE_DECOMPRESS))
+		message_fatal(_("With --format=raw, --suffix=.SUF is "
+				"required unless writing to stdout"));
+
 	// If no filenames are given, use stdin.
 	if (argv[optind] == NULL && args->files_name == NULL) {
 		// We don't modify or free() the "-" constant. The caller

src/xz/suffix.c

@@ -131,15 +131,7 @@ uncompressed_name(const char *src_name, const size_t src_len)
 	const char *new_suffix = "";
 	size_t new_len = 0;
 
-	if (opt_format == FORMAT_RAW) {
-		// Don't check for known suffixes when --format=raw was used.
-		if (custom_suffix == NULL) {
-			message_error(_("%s: With --format=raw, "
-					"--suffix=.SUF is required unless "
-					"writing to stdout"), src_name);
-			return NULL;
-		}
-	} else {
+	if (opt_format != FORMAT_RAW) {
 		for (size_t i = 0; i < ARRAY_SIZE(suffixes); ++i) {
 			new_len = test_suffix(suffixes[i].compressed,
 					src_name, src_len);
@@ -262,15 +254,6 @@ compressed_name(const char *src_name, size_t src_len)
 		}
 	}
 
-	// TODO: Hmm, maybe it would be better to validate this in args.c,
-	// since the suffix handling when decoding is weird now.
-	if (opt_format == FORMAT_RAW && custom_suffix == NULL) {
-		message_error(_("%s: With --format=raw, "
-				"--suffix=.SUF is required unless "
-				"writing to stdout"), src_name);
-		return NULL;
-	}
-
 	const char *suffix = custom_suffix != NULL
 			? custom_suffix : suffixes[0];
 	size_t suffix_len = strlen(suffix);
@@ -409,3 +392,10 @@ suffix_set(const char *suffix)
 	custom_suffix = xstrdup(suffix);
 	return;
 }
+
+
+extern bool
+suffix_is_set(void)
+{
+	return custom_suffix == NULL;
+}

src/xz/suffix.h

@@ -26,3 +26,10 @@ extern char *suffix_get_dest_name(const char *src_name);
 /// suffix, thus if this is called multiple times, the old suffixes are freed
 /// and forgotten.
 extern void suffix_set(const char *suffix);
+
+/// \brief      Check if a custom suffix has been set
+///
+/// Returns true if the internal tracking of the suffix string has been set
+/// and false if the string has not been set. This will keep the suffix
+/// string encapsulated instead of extern-ing the variable.
+extern bool suffix_is_set(void);